使用数字电位器设计低通可调滤波器

Themostcommonfilterfoundinadataacquisition

systemsignalpathisalow-passfilter.Thistypeoffilter

isusuallyusedtoreduceA/DConverter(ADC)aliasing

errors.Ifthereismorethanonesignalthatisappliedto

theA/Dconverterthroughamultiplexer,eachsignal

sourcemayhaveitsownsetoffilterrequirements(i.e.,

settlingtime,fasttransitionregion,etc.).Consequently,

avarietyoffiltersmayberequiredinthecircuitpriorto

themultiplexer.Usuallythesefiltersareimplemented

withoperationalamplifiers(opamps)incombination

withfixedresistorsandcapacitors.MAN737UsingDigitalPotentiometerstoDesignLow-PassAdjustableFiltersblecornerfrequencyrangeof1:100.AnexampleoftheAuthor:BonnieC.BakerdigitalpotentiometersettingforthesedesignsisMicrochipTechnologyInc.summarizedinTables1,2and3.Thefourthscenariowillshowthesamecircuitdesign,whereallthreeINTRODUCTION